Wireless charging of devices in accordance with schedule and/or priority

ABSTRACT

Some embodiments provide a system for charging devices. The system includes a master device and a slave device. Some embodiments provide a method for charging devices in a system that includes a slave device and a master device. The slave device includes (1) an antenna to receive a radio frequency (RF) beam and (2) a power generation module connected to the antenna that converts RF energy received by the slave antenna to power. The master device includes (1) a directional antenna to direct RF power to the antenna of the slave device and (2) a module that provides power to the directional antenna of the master device.

CLAIM OF BENEFIT TO RELATED APPLICATIONS

The present application is a continuation application of U.S. patentapplication Ser. No. 15/610,494, entitled “Wireless Charging of Devicesin a Car,” filed May 31, 2017, which is a continuation application ofU.S. patent application Ser. No. 15/263,629, entitled “SelectiveWireless Charging of Authorized Slave Devices,” filed Sep. 13, 2016,which is a continuation application of U.S. patent application Ser. No.14/223,841, entitled “Method and Apparatus for Wirelessly TransferringPower and Communicating with One or More Slave Devices,” filed Mar. 24,2014, now U.S. Pat. No. 9,608,472, which is itself a continuationapplication of U.S. patent application Ser. No. 12/979,254, entitled“Method and apparatus for wirelessly transferring power andcommunicating with one or more slave devices,” filed Dec. 27, 2010, nowU.S. Pat. No. 8,686,685. U.S. patent application Ser. No. 12/979,254claims the benefit of and priority to U.S. Provisional PatentApplication 61/290,184, entitled, “Master Device that WirelesslyTransfers Power and Communicates with a Plurality of Slave Devices,”filed Dec. 25, 2009. The contents of all of the above-identifiedapplications are hereby incorporated fully by reference into the presentapplication.

BACKGROUND

Induction is a common form for wireless power. Non resonant inductionsystems like transformers use a primary coil to generate a magneticfield. A secondary coil is then placed in that magnetic field and acurrent is induced in the secondary coil. Induction, however, has thedisadvantage that the receiver must be very close to the transmitter inorder to inductively couple to it. At large distances induction wastesmost of the energy in the resistive losses of the primary coil. Resonantinductive coupling improves energy transfer efficiency at largerdistances by using two coils that are highly resonant at the samefrequency. However, both non-resonant and resonant induction wirelesspower methods are non-directive and irradiate the space around them.This can be disadvantage in some situations since there are regulationsthat limit human exposure to alternating magnetic fields because ofconcern for biological impacts on the users. Also, since they use lowfrequencies (KHz to 7 MHz) they cannot be used for high speedcommunication.

BRIEF SUMMARY

The preceding Summary is intended to serve as a brief introduction tosome embodiments of the invention. It is not meant to be an introductionor overview of all inventive subject matter disclosed in this document.The Detailed Description that follows and the Drawings that are referredto in the Detailed Description will further describe the embodimentsdescribed in the Summary as well as other embodiments. Accordingly, tounderstand all the embodiments described by this document, a full reviewof the Summary, Detailed Description and the Drawings is needed.Moreover, the claimed subject matters are not to be limited by theillustrative details in the Summary, Detailed Description and theDrawing, but rather are to be defined by the appended claims, becausethe claimed subject matters can be embodied in other specific formswithout departing from the spirit of the subject matters.

Some embodiments provide a wireless transmitter that uses radiofrequencies (RF) with small high gain directive antennas and highfrequency radio waves or electromagnetic induction to charge one or morereceiving devices and then communicate with them. Wireless communicationis convenient because it allows devices to connect to each other withoutwires. Wireless power is convenient because it removes the need forwires and connectors. This invention combines these two aspectstogether.

Some embodiments use radio frequency (RF) instead of resonantelectromagnetic induction to charge and communicate with slave devices.Throughout this specification the 60 GHz spectrum is used for describingthe RF charging aspect of this invention. However, 60 GHz is only onespecial case of using higher frequencies for implementing thisinvention. In the U.S. the 60 GHz spectrum band can be used forunlicensed short range data links (1.7 km) with data throughputs up to2.5 Gbits/s. Higher frequencies such as the 60 GHz spectrum experiencestrong free space attenuation. The smaller wavelength of such highfrequencies also enables the use of small high gain antennas with smallbeam widths. The combination of high attenuation and high directiveantenna beams provides better frequency reuse so that the spectrum canbe used more efficiently for point-to-multipoint communications. Forexample, a larger number of directive antennas and users can be presentin a given area without interfering with one another, compared to lessdirective antennas at lower frequencies. Small beam width directiveantennas also confine the electromagnetic waves to a smaller space andtherefore limit human exposure. The higher frequencies also provide morebandwidth and allow more information to be wirelessly transmitted. Thus,the same antenna can be used to for power generation and communication.

There are several standards bodies that are using high frequencies suchas 60 GHz. These include WirelessHD, WiGig, and WiFi IEEE 802.11 ad. TheWirelessHD specification is based on the 7 GHz of continuous bandwidtharound the 60 GHz radio frequency and allows for digital transmission ofuncompressed high definition (HD) video, audio and data. It is aimed atconsumer electronics applications and provides a digital wirelessinterface for file transfers, wireless display and docking, and losslessHD media streaming for ranges up to 10 meters. Theoretically it cansupport data rates as high as 25 Gbit/s. The 60 GHz band usuallyrequires line of sight between transmitter and receiver because of highabsorption. The WirelessHD specification gets around this limitation byusing beam forming at the transmitter and receiver antennas to increaseeffective power of the signal.

The WiGig standard (short for the “Wireless Gigabit Alliance”) is alsopromoting high speed wireless communication over the unlicensed 60 GHzspectrum and is a competing standard to WirelessHD. The WiGig standardis also taking advantage of the high absorption of 60 GHz that limitssignal propagation and reduces interference with other wireless systems.

IEEE 802.11ad is also under development by the IEEE task group for theupcoming 60 GHz standard. This is essentially a faster version of theIEEE 802.11 standard that uses the 60 GHz band. However, because it usesa new spectrum it will not be backward compatible with existing WiFi.

Wireless USB is a standard which does not use 60 GHz. Wireless USB usesthe Ultra-wideBand (UWB) radio platform that operates in the 3.1 to 10.6GHz frequency and can transmit 480 Mbit/s at distances up to 3 metersand 110 Mbit/s at up to 10 meters. While the goal of 802.11 family(802.11*) WiFi is to replace Ethernet cables and provide wirelessInternet access, the goat of Wireless USB is to remove the cables fromUSB based PC peripherals. Wireless USB can be used for printers,scanners, digital cameras, MP3 players, game controllers, hard disks,and flash drives. Both WirelessHD and WiGig are competing in someaspects with the Wireless USB standard. Inductive Charging in someembodiments is performed at lower frequencies such as frequencies ofless than 100 MHz, whereas RF frequencies used in some embodiments isgreater than 900 MHz or 1 GHz. The higher the RF frequencies, thesmaller the wavelength and hence the smaller the size of the antenna.

None of the above standards address charging slave devices beforecommunicating with them. Instead they assume that the slaves have accessto some power source such as AC power or a battery. In some embodimentsa master device uses one or more directional antennas or uses antennaarray beam forming to transmit high frequency RF signals to one or moreslave devices to power them up or charge their batteries. By using thedirectional antennas or using antenna array beam forming, theseembodiments concentrate the power on a smaller area.

Some embodiments provide a networked system with a master device thatcan power-up or charge a plurality of slave devices and communicate withthem. In some embodiments the master is connected to other networkdevices and/or Intranet/Internet though packet-based or non packet basednetworks and wired or wireless networks (such as Bluetooth®, WirelessLocal Area Network (WLAN), fourth generation (4G) cellular, CodeDivision Multiple Access (CDMA), Time Division Multiple Access (TDMA),Worldwide Interoperability for Microwave Access (WiMAX), UWB and 60GHz). The master in some embodiments monitors the power status of aplurality of slaves, decides which subset of those slaves get chargedand what their charging priorities are. The slaves in some embodimentshave different power status and capabilities (some have power tocommunicate, while others have low battery, and yet others have nobattery).

In some embodiments, the slave has sensors (e.g. temperature, gyrator,pressure, and heart monitor) with electronic circuitry that are poweredup by the master, perform their sensing functions and communicate theirdata to the master, a network server, or some other device. The channelfor power transfer in some embodiments is RF or electromagneticinduction. A control channel is used in some embodiments by the masterto send commands to the slaves. Some embodiments use the same channelfor power, control, and communication. One, two or all of the power,control, and communication in some embodiments use different channels(e.g. different frequencies, different radios, different antenna, anddifferent coils for induction) or different methods (RF Beam andinduction).

In some embodiments, the master configures the system to increase powerand communication efficiency (e.g. uses several antenna and beamsteering for RF, or several coils and coil pattern optimization forinduction). In some embodiments the master and the slave have a matrixof coils (for induction) and the master changes it's transmit coilpattern in order to optimize power transfer to the slave. Severalmasters in some embodiments cooperate or are configured by a networkserver or remote user to use beam steering and different antennas tocharge a plurality of slaves. In some embodiments the slaves providetheir identifying information and register themselves in a slaveinformation database. In some embodiments the masters provide theiridentifying information and register themselves in a master informationdatabase. The master in some embodiments receives a slave's identifyinginformation (MAC ID, network Internet protocol (IP) address, name,serial number, product name and manufacturer, capabilities, etc.) bycommunicating with the slave or by examining the slave informationdatabase to select which slaves to power up, charge, or communicatewith. A slave in some embodiments prevents non-authorized masters (ornetworked servers) from trying to charge it or power it up by checkingthe master's identifying information with the authorized master's liststored on the slave. The master's selection and power scheduling ofslaves is dependent on the priorities of slaves' functions and data insome embodiments.

In some embodiments, the master uses frequency hopping and time hoppingto select some slaves from a plurality of slaves. A master in someembodiments charges a slave to a pre-set high level, then communicateswith it until battery falls to a pre-set low level, and then chargesslave again, etc. A master in some embodiments powers-up/charges aslave's battery and communicate with the slave at the same time. In someembodiments a slave that is powered up gets connected to a network(packet-based or non packet based, wired or wireless such as Bluetooth®,WLAN, 4G cellular, CDMA, TDMA, WiMax, UWB and 60 GHz) through themaster, through other nearby slaves, or directly to an accesspoint/tower.

A master that does not have a network connection in some embodimentscharges a slave and uses the slave's network connection to connect tothe network and perform networked operations such as downloadingsoftware and driver upgrades. In some embodiments a slave that ispowered up and charged becomes a master charger for other slaves.

The master and the slave optionally have a touch screen and/or keyboardfor entering data which can be displayed on the screen and/orcommunicated, respectively, to the slave and the master in someembodiments. A network server that is connected to the master iseffectively the real master in some embodiments and instructs themaster, monitors the power status of a plurality of slaves, decideswhich subset of those slaves are powered up/charged/communicate with,and what their priorities are. Also, an authorized remote user in someembodiments uses the network to connect to the network server andcontrol the network server, which in turn instructs the masters tomonitor the power status of a plurality of slaves, decide which subsetof those slaves are powered up/charged/communicate with, and what theirpriorities are.

A non-conductive spacer is used in some embodiments to create aseparation distance of several wavelengths for RF charging andcommunication. Networked master chargers (both RF and induction) are insome embodiments built-in to conference room tables, office tables orlightweight pads so that meeting participants are able to wirelesslycharge their devices, connect to each other or to the Intranet/Internet,transmit/receive information, and make payment transactions. Multi-coilinduction masters, tables or pads in some embodiments have a credit cardreader. Similarly, RF masters in some embodiments include credit cardreaders, so users can “sweep” their card for magnetic cards or they canread NFC-enabled cards with NFC. Therefore, users of slaves are not onlyable to charge their devices but also make payment transactions. Forinstance, phones with near field communication (NFC) capabilities insome embodiments are charged and are also used for contactless paymentso that the user places the phone near those coils (or RF beams of amaster in the case of RF-based master) in order to transmit paymentinformation to a secured server on the Internet. Alternatively, creditcards in some embodiments have a chip so that they transmit theirinformation to the master device.

Some of the coils of a multi-coil master (or RF beams of a master in thecase of a multi-antenna RF-based master) in some embodiments arededicated and optimized for communication, while others are optimizedfor charging. The master has different means for power, e.g., one ormore of AC and adaptor, battery, induction, etc.

In some embodiments, a master uses an external induction charger to getcharged, and then uses a high frequency directional and focused RF beamto power up a slave device and communicate with it. A master usesinduction in some embodiments to charge a slave and uses a communicationtransceiver (e.g. a high frequency directional and focused RF beam) tocommunicate with the slave. Two or more slaves are charged by a masterinduction charger in some embodiments and then communicate with eachother directly or through the master, possibly under the control of aremote network server.

In some embodiments an element is designed for the master, slave or bothso that at low frequencies the element is like a coil inductor and athigh frequencies the element is like an antenna. This means that at thesame time both RF power and induction power are available. If thedistance is short then waves cannot be created and it will be more likeinduction. So distance is used to select one mode or the mode is chosenautomatically. In other embodiments, the master, slave or both to havetwo different elements for different distances (one for short distancesand one for far distances). In some of these embodiments, the masterdoes time multiplexing between the two or select one over the other. Insome embodiments, an element is designed to be a coil at low frequenciesand a multiple antenna at high frequencies with beam formingcapabilities. The length of the coil is much bigger than the size ofantenna required for RF at high frequencies. In some embodiments, thiscoil is divided into multiple RF antennas and the resulting multipleantennas is used to do beam forming.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth in the appendedclaims. However, for purpose of explanation, several embodiments of theinvention are set forth in the following figures.

FIG. 1 conceptually illustrates an overview of the networked aspect ofsome embodiments of the invention.

FIG. 2 conceptually illustrates an overview of the system of someembodiments of the invention where the slave does not have a battery.

FIG. 3 conceptually illustrates an alternative system of someembodiments of the invention where the slave has a battery.

FIG. 4 illustrates a more detailed diagram of the embodiments shown inFIGS. 2 and 3.

FIG. 5 conceptually illustrates a process for master-slave charging andcommunication in some embodiments of the invention.

FIG. 6 conceptually illustrates a master two different transmitters forpower generation and communication in some embodiments of the invention.

FIG. 7 conceptually illustrates a master and a slave that each includetwo separate antennas/transceivers, one for power generation and one forcommunication in some embodiments of the invention.

FIG. 8 conceptually illustrates a master in some embodiments of theinvention that uses beam steering to change the direction of the beamwhen the slave is not directly in front of its beam.

FIG. 9 conceptually illustrates a multi-antenna RF master that has anon-conductive spacer material in front of its antenna in someembodiments of the invention.

FIG. 10 conceptually illustrates a master that uses induction to chargeand communicate with a slave in some embodiments of the invention.

FIG. 11 conceptually illustrates a master in some embodiments of theinvention that uses the power transmitter for charging, and a separatetransmitter for data transmission.

FIG. 12 conceptually illustrates a master that has a power transmitterfor each of its coils in some embodiments of the invention.

FIG. 13 conceptually illustrates a master in some embodiments of theinvention with coils that have the same frequency and a multiplexer toactivate coils at different times.

FIG. 14 conceptually illustrates induction between the master and theslave by using more than one coil on the master or the slave in someembodiments of the invention.

FIG. 15 conceptually illustrates a process of some embodiments of theinvention to change a master device's coil pattern in some embodimentsof the invention.

FIG. 16 conceptually illustrates a multi-coil slave with inductioncharging in some embodiments of the invention.

FIG. 17 conceptually illustrates a process for reconfiguring coils of aslave device in some embodiments of the invention.

FIG. 18 conceptually illustrates a process for terminating powergeneration in the slave in some embodiments of the invention.

FIG. 19 conceptually illustrates a process for configuring the slave'scoils for either power generation or data transmission in someembodiments of the invention.

FIG. 20 conceptually illustrates a hybrid system of some embodiments ofthe invention where the master uses an induction charger as a powersource to power itself and then uses a high frequency directional andfocused RF beam to power up one or more slave devices and communicatewith them.

FIG. 21 conceptually illustrates a master in some embodiments of theinvention that acts as an induction charger and uses induction to chargethe slave before using its high frequency directional beam tocommunicate with the slave.

FIG. 22 conceptually illustrates two slaves in some embodiments of theinvention that use the power of a master's coils to power up or chargetheir batteries and then communicate with each other using theircommunication transceivers.

FIG. 23 conceptually illustrates an element in some embodiments of theinvention that is designed to be a coil at low frequencies and amultiple antenna at high frequencies with beam forming capabilities.

FIG. 24 conceptually illustrates a computer system with which someembodiments of the invention are implemented.

DETAILED DESCRIPTION

In the following detailed description of the invention, numerousdetails, examples, and embodiments of the invention are set forth anddescribed. However, it will be clear and apparent to one skilled in theart that the invention is not limited to the embodiments set forth andthat the invention may be practiced without some of the specific detailsand examples discussed.

Some embodiments provide a wireless transmitter that uses radiofrequencies (RF) with small high gain directive antennas and highfrequency radio waves or electromagnetic induction to charge one or morereceiving devices and then communicate with them. Wireless communicationis convenient because it allows devices to connect to each other withoutwires. Wireless power is convenient because it removes the need forwires and connectors. This invention combines these two aspectstogether.

Some embodiments use radio frequency (RF) instead of resonantelectromagnetic induction to charge and communicate with slave devices.Throughout this specification the 60 GHz spectrum is used for describingthe RF charging aspect of this invention. However, 60 GHz is only onespecial case of using higher frequencies for implementing thisinvention. In the U.S. the 60 GHz spectrum band can be used forunlicensed short range data links (1.7 km) with data throughputs up to2.5 Gbits/s. Higher frequencies such as the 60 GHz spectrum experiencestrong free space attenuation. The smaller wavelength of such highfrequencies also enables the use of small high gain antennas with smallbeam widths. The combination of high attenuation and high directiveantenna beams provides better frequency reuse so that the spectrum canbe used more efficiently for point-to-multipoint communications. Forexample, a larger number of directive antennas and users can be presentin a given area without interfering with one another, compared to lessdirective antennas at lower frequencies. Small beam width directiveantennas also confine the electromagnetic waves to a smaller space andtherefore limit human exposure. The higher frequencies also provide morebandwidth and allow more information to be wirelessly transmitted. Thus,the same antenna can be used to for power generation and communication.

There are several standards bodies that are using high frequencies suchas 60 GHz. These include WirelessHD, WiGig, and WiFi IEEE 802.11ad. TheWirelessHD specification is based on the 7 GHz of continuous bandwidtharound the 60 GHz radio frequency and allows for digital transmission ofuncompressed high definition (HD) video, audio and data. It is aimed atconsumer electronics applications and provides a digital wirelessinterface for file transfers, wireless display and docking, and losslessHD media streaming for ranges up to 10 meters. Theoretically it cansupport data rates as high as 25 Gbit/s. The 60 GHz band usuallyrequires line of sight between transmitter and receiver because of highabsorption. The WirelessHD specification gets around this limitation byusing beam forming at the transmitter and receiver antennas to increaseeffective power of the signal.

The WiGig standard (short for the “Wireless Gigabit Alliance”) is alsopromoting high speed wireless communication over the unlicensed 60 GHzspectrum and is a competing standard to WirelessHD. The WiGig standardis also taking advantage of the high absorption of 60 GHz that limitssignal propagation and reduces interference with other wireless systems.

IEEE 802.11ad is also under development by the IEEE task group for theupcoming 60 GHz standard. This is essentially a faster version of theIEEE 802.11 standard that uses the 60 GHz band. However, because it usesa new spectrum it will not be backward compatible with existing WiFi.

Wireless USB is a standard which does not use 60 GHz. Wireless USB usesthe Ultra-wideBand (UWB) radio platform that operates in the 3.1 to 10.6GHz frequency and can transmit 480 Mbit/s at distances up to 3 metersand 110 Mbit/s at up to 10 meters. White the goal of 802.11 family(802.11*) WiFi is to replace Ethernet cables and provide wirelessInternet access, the goal of Wireless USB is to remove the cables fromUSB based PC peripherals. Wireless USB can be used for printers,scanners, digital cameras, MP3 players, game controllers, hard disks,and flash drives. Both WirelessHD and WiGig are competing in someaspects with the Wireless USB standard. Inductive Charging in someembodiments is performed at lower frequencies such as frequencies ofless than 100 MHz, whereas RF frequencies used in some embodiments isgreater than 900 MHz or 1 GHz. The higher the RF frequencies, thesmaller the wavelength and hence the smaller the size of the antenna.

None of the above standards address charging slave devices beforecommunicating with them. Instead they assume that the slaves have accessto some power source such as AC power or a battery. In some embodimentsa master device uses one or more directional antennas or uses antennaarray beam forming to transmit high frequency RF signals to one or moreslave devices to power them up or charge their batteries. By using thedirectional antennas or using antenna array beam forming, theseembodiments concentrate the power on a smaller area.

Some embodiments provide a networked system with a master device thatcan power-up or charge a plurality of slave devices and communicate withthem. In some embodiments the master is connected to other networkdevices and/or Intranet/Internet though packet-based or non packet basednetworks and wired or wireless networks (such as Bluetooth®, WirelessLocal Area Network (WLAN), fourth generation (4G) cellular, CodeDivision Multiple Access (CDMA), Time Division Multiple Access (TDMA),Worldwide Interoperability for Microwave Access (WiMAX), UWB and 60GHz). The master in some embodiments monitors the power status of aplurality of slaves, decides which subset of those slaves get chargedand what their charging priorities are. The slaves in some embodimentshave different power status and capabilities (some have power tocommunicate, while others have low battery, and yet others have nobattery).

In some embodiments, the slave has sensors (e.g. temperature, gyrator,pressure, and heart monitor) with electronic circuitry that are poweredup by the master, perform their sensing functions and communicate theirdata to the master, a network server, or some other device. The channelfor power transfer in some embodiments is RF or electromagneticinduction. A control channel is used in some embodiments by the masterto send commands to the slaves. Some embodiments use the same channelfor power, control, and communication. One, two or all of the power,control, and communication in some embodiments use different channels(e.g. different frequencies, different radios, different antenna, anddifferent coils for induction) or different methods (RF Beam andinduction).

In some embodiments, the master configures the system to increase powerand communication efficiency (e.g. uses several antenna and beamsteering for RF, or several coils and coil pattern optimization forinduction). In some embodiments the master and the slave have a matrixof coils (for induction) and the master changes it's transmit coilpattern in order to optimize power transfer to the slave. Severalmasters in some embodiments cooperate or are configured by a networkserver or remote user to use beam steering and different antennas tocharge a plurality of slaves. In some embodiments the slaves providetheir identifying information and register themselves in a slaveinformation database. In some embodiments the masters provide theiridentifying information and register themselves in a master informationdatabase. The master in some embodiments receives a slave's identifyinginformation (MAC ID, network Internet protocol (IP) address, name,serial number, product name and manufacturer, capabilities, etc.) bycommunicating with the slave or by examining the slave informationdatabase to select which slaves to power up, charge, or communicatewith. A slave in some embodiments prevents non-authorized masters (ornetworked servers) from trying to charge it or power it up by checkingthe master's identifying information with the authorized master's liststored on the slave. The master's selection and power scheduling ofslaves is dependent on the priorities of slaves' functions and data insome embodiments.

In some embodiments, the roaster uses frequency hopping and time hoppingto select some slaves from a plurality of slaves. A master in someembodiments charges a slave to a pre-set high level, then communicateswith it until battery falls to a pre-set low level, and then chargesslave again, etc. A master in some embodiments powers-up/charges aslave's battery and communicate with the slave at the same time. In someembodiments a slave that is powered up gets connected to a network(packet-based or non packet based, wired or wireless such as Bluetooth®,WLAN, 4G cellular, CDMA, TDMA, WiMax, UWB and 60 GHz) through themaster, through other nearby slaves, or directly to an accesspoint/tower.

A master that does not have a network connection in some embodimentscharges a slave and uses the slave's network connection to connect tothe network and perform networked operations such as downloadingsoftware and driver upgrades. In some embodiments a slave that ispowered up and charged becomes a master charger for other slaves.

The master and the slave optionally have a touch screen and/or keyboardfor entering data which can be displayed on the screen and/orcommunicated, respectively, to the slave and the master in someembodiments. A network server that is connected to the master iseffectively the real master in some embodiments and instructs themaster, monitors the power status of a plurality of slaves, decideswhich subset of those slaves are powered up/charged/communicate with,and what their priorities are. Also, an authorized remote user in someembodiments uses the network to connect to the network server andcontrol the network server, which in turn instructs the masters tomonitor the power status of a plurality of slaves, decide which subsetof those slaves are powered up/charged/communicate with, and what theirpriorities are.

A non-conductive spacer is used in some embodiments to create aseparation distance of several wavelengths for RF charging andcommunication. Networked master chargers (both RF and induction) are insome embodiments built-in to conference room tables, office tables orlightweight pads so that meeting participants are able to wirelesslycharge their devices, connect to each other or to the Intranet/Internet,transmit/receive information, and make payment transactions. Multi-coilinduction masters, tables or pads in some embodiments have a credit cardreader. Similarly, RF masters in some embodiments include credit cardreaders, so users can “sweep” their card for magnetic cards or they canread NFC-enabled cards with NFC. Therefore, users of slaves are not onlyable to charge their devices but also make payment transactions. Forinstance, phones with near field communication (NFC) capabilities insome embodiments are charged and are also used for contactless paymentso that the user places the phone near those coils (or RF beams of amaster in the case of RF-based master) in order to transmit paymentinformation to a secured server on the Internet. Alternatively, creditcards in some embodiments have a chip so that they transmit theirinformation to the master device.

Some of the coils of a multi-coil master (or RF beams of a master in thecase of a multi-antenna RF-based master) in some embodiments arededicated and optimized for communication, while others are optimizedfor charging. The master has different means for power, e.g., one ormore of AC and adaptor, battery, induction, etc.

In some embodiments, a master uses an external induction charger to getcharged, and then uses a high frequency directional and focused RF beamto power up a slave device and communicate with it. A master usesinduction in some embodiments to charge a slave and uses a communicationtransceiver (e.g. a high frequency directional and focused RF beam) tocommunicate with the slave. Two or more slaves are charged by a masterinduction charger in some embodiments and then communicate with eachother directly or through the master, possibly under the control of aremote network server.

In some embodiments an element is designed for the master, slave or bothso that at low frequencies the element is like a coil inductor and athigh frequencies the element is like an antenna. This means that at thesame time both RF power and induction power are available. If thedistance is short then waves cannot be created and it will be more likeinduction. So distance is used to select one mode or the mode is chosenautomatically. In other embodiments, the master, slave or both to havetwo different elements for different distances (one for short distancesand one for far distances). In some of these embodiments, the masterdoes time multiplexing between the two or select one over the other. Insome embodiments, an element is designed to be a coil at low frequenciesand a multiple antenna at high frequencies with beam formingcapabilities. The length of the coil is much bigger than the size ofantenna required for RF at high frequencies. In some embodiments, thiscoil is divided into multiple RF antennas and the resulting multipleantennas is used to do beam forming.

Some embodiments provide a system for charging devices. The systemincludes a master device and a slave device. Some embodiments provide amethod for charging devices in a system that includes a slave device anda master device. The slave device includes (1) an antenna to receive aradio frequency (RF) beam and (2) a power generation module connected tothe antenna that converts RF energy received by the slave antenna topower. The master device includes (1) a directional antenna to direct RFpower to the antenna of the slave device and (2) a module that providespower to the directional antenna of the master device.

Some embodiments provide a system for charging devices. The systemincludes a master device and a slave device. Some embodiments provide amethod for charging devices in a system that includes a slave device anda master device. The master device includes a first group of coils totransmit energy by induction. The first group of coils is arranged in afirst pattern. The master device also includes a module that providesalternating power to the first group of coils. The master device alsoincludes a processing module. The slave device includes a second groupof coils to receive energy by induction from one or more coils of themaster device. The second plurality of coils is arranged in a secondpattern. The slave also includes a power generation module connected tothe second group of coils that converts the received induction energy topower. The master processing unit (i) receives information from theslave regarding the slave coil pattern and (ii) based on the receivedinformation, activates a set of coils in the first group of coils tooptimize an amount of induction energy received by the second group ofcoils.

In some embodiments, the processing module (i) receives informationregarding the amount of induction energy received by the second group ofcoils and (ii) when the induction energy received by the second group ofcoils does not satisfy a threshold, activates a different set of coilsin the first group of coils to further optimize an amount of inductionenergy received by the second group of coils.

Some embodiments provide a system for charging devices. The systemincludes a master device and a slave device. Some embodiments provide amethod for charging devices in a system that includes a slave device anda master device. The master device includes a first group of coils totransmit energy by induction. The master device also includes a modulethat provides alternating power to the first group of coils. The slavedevice includes a second group of coils to receive energy by inductionfrom one or more coils of the master device. The second group of coilshas a set of operating parameters. The slave also includes a powergeneration module connected to the second group of coils that convertsthe received induction energy to power. The slave also includes aprocessing module. The slave processing unit (i) receives a set ofmaster device's parameters and (ii) based on the received masterdevice's parameters, reconfigures one or more of the operatingparameters of the second group of coils to maximize the receivedinduction power.

In some embodiments, the master device's parameters include an operatingfrequency of the master's induction frequency, data and modulationmethod used by the master, and an identifying information of the master.In some embodiments, the operating parameters of the slave device arereconfigured by tuning of one or more coils in the second plurality ofcoils. In some embodiments, the operating parameters of the slave deviceare reconfigured by calibrating of one or more coils in the second groupof coils. In some embodiments the operating parameters of the slavedevice are reconfigured by impedance matching of one or more coils inthe second group of coils.

Several more detailed embodiments of the invention are described insections below. Section I provides an overview of several embodiments ofthe invention. Section II describes different embodiments of theinvention that provide charging remote device using RF beams. Next,Section III describes several embodiments that charge remoter devicesusing induction. Section IV discusses hybrid embodiments that chargeremote devices using both RF beams and induction. Finally, section Vprovides a description of a computer system with which some embodimentsof the invention are implemented.

I. Overview

A. Charging and Communicating with One or More Slaves

FIG. 1 conceptually illustrates an overview of the networked aspect ofsome embodiments of the invention. Masters in some embodiments chargeand communicate with one or more of the slave devices within thenvicinity. The master in some embodiments is connected to other networkdevices. In the example of FIG. 1, master A 105 is connected using awireless channel (packet-based system or non-packet based system,Bluetooth®, WLAN, 4G cellular, CDMA, TDMA, WiMax, UWB and 60 GHz, etc.)through an access point 155 to a network 110 and powers up slaves 1 and2. Master B 115 has multiple antennas 117, is connected to a network 110using a wireline, and powers up slaves 3, 4 and 5. Master C 120 is alsoconnected to a network 110 using a wireline. Master B 115 and master C120 cooperate (or are controlled by a controller device such as networkserver 135 or remote user 140) and use beam steering to charge slave 6.The slaves differ in their power status and capability in someembodiments. Some slaves have power and communicate, white others havelow battery, and yet others have no battery. The charging of the slavesis done wirelessly with methods such as a resonant electromagnetic,induction channel or an RF channel.

B. Power Transfer to Authorized Slaves

Charging in some embodiments is initiated by the slave or by the masterwhen the two are close to each other (for example either automaticallyor by pressing a button on the slave or the master, respectively). Amaster selects which slaves to power up and communicate with in sortieembodiments. The slaves have identifying information about themselvesstored in their memories. This stored information includes one or moreof the slaves' media access control address (MAC address or MAC ID),network IP address, name, serial number, product name and manufacturer,capabilities, etc. The master (or a controller device such as a networkserver, or a remote user) requests that information. In someembodiments, the slaves are proactive and communicate with the master(or a controller device such as a network server, or a remote user) ifthey have power (e.g. charge my battery, I want to send you some data,etc.) and provide their identifying information and register themselvesin a slave information database. In some embodiments, the master hasaccess to a slave information database that includes an authorized list.This database is locally stored 125 on the master 115 or it is stored ona possibly larger networked database 130.

In some embodiments, a master that employs a focused directional RF beamuses beam steering to focus the beam on a particular slave, power theslave up slightly to get slave's identifying information, and onlycontinue powering up/charging and communication if the slave'sidentifying information match with an entry on the authorized list. Forinstance, only a slave with a certain MAC ID, network IF address, name,serial number, product name, manufacturer, capabilities, etc. may bepowered up, charged or communicated with. For RF-based methods frequencyhopping methods are also used in some embodiments by the master andauthorized slaves to allow them to get power while unauthorized nearbyslaves (that do not know the hopping sequence) do not receive muchpower. Similarly, a master that employs focused RF beams uses timehopping to power up slaves.

A master that uses resonant induction uses the right resonant frequencythat matches the slave, coil matrix frequency hopping, coil matrix timehopping, and current/voltage to power up a nearby authorized slave insome embodiments. The slave's identifying information is communicated bythe slave to the master in some embodiments if the slave has some power(communicated using RF communication, backscattering, infrared or othermethods), or communicated after an initial sub-optimal power-up. Again,the master only transfers power to the slave if the slave's identifyinginformation match with an entry on an authorized list. In someembodiments, the slave's resonant frequency is stored at the master(e.g., in slave information database 125) or at a network database(e.g., in slave information database 130).

C. Power Transfer only from Authorized Masters

A slave prevents non-authorized masters from trying to charge it orpower it up (or networked servers from commanding masters to charge itor power it up) in some embodiments. Slaves store identifyinginformation about masters (or networked servers) that are authorized tocharge them. The stored information about authorized masters ornetworked servers includes one or more of the following informationabout the masters: the masters' media access control address (MAC ID),network IP address, name, serial number, product name and manufacturer,capabilities, etc. The slave requests identifying information from themaster or the network server. The master (or the network server) in someembodiments is also proactive and sends its identifying information tothe slave. The masters in some embodiments also register themselves andtheir identifying information in a master information database 150. Theslave in some embodiments checks the master's information with theauthorized list and if there is not a match the slave disables chargingand/or power-up.

D. Master's Scheduling of Slaves

The selection and power scheduling of slaves in some embodiments aredependent on the priorities of slaves' functions or data (e.g. slave 1with a higher priority gets 5 minutes scheduled for charging and slave 2with a tower priority gets 3 minutes). A slave information database 125stored at the master 115 or a slave information database 130 stored onthe network include priorities for slaves and their data in someembodiments. The slaves also communicate their data (and possibly thepriority of their data) to the master in some embodiments. Based on thisinformation the master then decides on a course of action.

E. Charging and Communication Strategies

The power status of slaves and their power-related requests and themaster's response strategy vary significantly in different embodiments.The followings are several examples: (1) slave has battery and power andis ready to communicate. Master may communicate; (2) slave has batteryand some charge, and slave requests to communicate. Master may allowcommunication or overrule and charge the slave further first (e.g. ifafter communicating the quality of slave data is not high because of thelow power status of slave); (3) slave has battery and some charge, butslave requests to be fully charged. Master may honor the request andcharge the slave or may overrule and communicate with the slave (e.g. iflive communication has higher priority); (4) slave has battery butbattery has no charge. Master may charge the battery first or just powerup the slave and communicate First if communication priority is high;(5) for options 1, 2, 3, and 4 above if after communicating a slave'sbattery charge level reaches zero or some pre-determined tow level thenthe battery is charged to some higher pre-determined level beforeresuming communication; (6) for options 1, 2, 3, and 4 above if there issufficient power transferred from the master to the slave then the slavemay communicate at the same time that the master is charging thebattery; (7) slave has battery and after it is charged by the master toa sufficient level the slave connects and communicates with nodes inanother network (e.g. slaves 1 and 3 connect to Bluetooth, WLAN, 4Gcellular, WiMax, UWB, 60 GHz and mesh ad-hoc networks). The masteroptionally continues to charge the slave or charge the slave once theslave's battery levels reach pre-set tow levels; (8) slave has nobattery and needs to be powered up before communication. Master powersup the slave before communicating (e.g. slave 2 in FIG. 1).

F. Charging Channel, Communication Channel and Control Channel

In some embodiments the same channel is used for both charging the slaveand communication, while in other embodiments different channels areused for charging and communication (e.g. two RF channels possibly withdifferent frequencies—one for charging and one for communication, orcharging with resonant induction and communication with RF). In someembodiments, the master also uses a control channel to inform the slaveswhat it wants to do. Thus, all the commands could come over the controlchannel, although it is also possible to send commands over the datacommunication channel as well. The control channel does not need to havehigh bandwidth. Thus, while the communication channel and the controlchannel use the same frequency in some embodiments, the control channeluses a lower frequency lower bandwidth channel than the communicationchannel. The master may also use an induction charger or RF charger tocharge its own battery if its power source is a rechargeable batteryinstead of AC power.

G. Connecting to New Networks for Slaves and/or Master

When the master is connected to a network (packet-based or nonpacket-based, Bluetooth®, WLAN, 4G cellular, TDMA, CDMA, WiMax, UWB, 60GHz, etc., or wired connection) then a powered up or charged slave isalso connected to the same network through the master (e.g. slave 4 inFIG. 1). Likewise, when a slave is connected to a network (Bluetooth®,WLAN, 4G cellular, WiMax, UWB, 60 GHz, etc., or wired connection) thenthe master gets connected to that network after the master charges thatslave (e.g. slave 3 and Master B 115 in FIG. 1). Thus, after powering upslave 3 not only is slave 3 able to connect to its wireless network(Bluetooth®, WLAN, 4G cellular, WiMax, UWB, 60 GHz, etc.) but master B115 is also able to connect to those networks through slave 3 acting asa network node. If a master does not have a network connection and aslave does the master in some embodiments charges the slave and use itsnetwork connection to connect to the network and perform networkedoperations such as downloading software and driver upgrades.

H. Slave Mesh Networks

A slave that gets powered up acts as a network node and communicate withother slaves in some embodiments. For instance, in FIG. 1 slave 1 isinitially powered up by master A 105. Master A 105 cannot communicatewith slave 7 because slave 7 is not within its communication range.However, master A 105 can communicate with slave 1, and slave 1 can inturn communicate with slave 7. Likewise, slave 7 can communicate withslave 8, etc. Thus, by charging slave 1 the master has connected itselfto a mesh network of slaves and other networks that it was not connectedto before.

I. Slave Becoming Chargers

Slaves that get charged act as masters and charge other slaves in someembodiments. In FIG. 1 slave 5 is charged by master B 115. Slave 9 alsoneeds to be charged. In this example, slave 5 charges slave 9. This mayfor example be because slave 9 is too far from master B for charging.

J. Network Server or Remote User Controls the Master

The explanations above assume that masters A and B control the decisionmaking in FIG. 1. It is also possible that a network server is incommand and is the “real” master. For example, the net-work server 135instructs master B 115 to power up the slaves in its vicinity andrequests information from the slaves. Master B 115 then sends theslaves' identifying information and any matching entries it has in itsown database 125 (together with any slave requests) to the networkserver 135, the network server further searches the networked slaveinformation database 130 for additional identifying and matchinginformation, and then instructs the master on a course of action (e.g.charge slaves 1 and 3, but no further action with unauthorized slave 4).In some embodiments, an authorized remote user 140 uses the network 110to connect to the network server 135 and control the network server,which in turn controls the masters as just described. Thus, depending onwhich component is in control (remote user, network server, or a master)that component monitors the power status of a plurality of slaves,decides which subset of those slaves get charged and what their chargingpriorities are.

II. Charging with RF

In some embodiments, the master uses a narrow focused RF beam forcharging. Converting RF signals to DC power has been done inRadio-Frequency Identification (RFID) far field applications. In nearfield RFID applications, where the distance between the RFID reader andthe tag is less than the wavelength of the signal, mutual inductance isused for communication. However, in far fields RFID applications, wherethe separation distance between the RFID reader and the tag is muchgreater than the wavelength of the signal, backscattering is used forcommunication. With backscattering a tag first modulates the receivedsignal and then reflects it back to the reader. There are severalimportant differences between the disclosed embodiments of the currentinvention and those of far field RFID which are described through tinsspecification. For instance, RFID does not use directional beams andhence spreads the power of the transmission over a wider space andunnecessarily exposes humans to electromagnetic radiation. RFID tagsalso require little power to operate (e.g. the receive power is of theorder of 200 microwatts) compared to the slave devices that thedisclosed embodiments of the current invention powers-up andcommunicates with. For instance, the receive power for the slaves insome embodiments of the invention is of the order of milliwatts andhigher. The upper receive power range depends on the transmit driversand the size of the coils or antennas, and in some embodiments goesabove the Watt range. RFID operates in lower frequencies (e.g. less than960 MHz) and hence provides smaller communication bandwidths andrequires much bigger antennas compared to the higher frequencies used indifferent embodiments of the current invention. Also, RFID usesbackscattering for communication which is a low data rate method becausethe antenna is turned on and off by the data like an on-off modulationswitch. The embodiments of the current invention provide a much higherdata rate because standard wireless transceiver modulation methods areused (e.g. modulations for cellular, 802.11*, Bluetooth®) and then thedata is sent to the antenna.

In contrast to RFID, some embodiments of the current invention usenarrow directional focused beams in order to simulate a wire connectionfor charging and communication. This focusing of the beam provides morepower and energy for charging slave devices. A directional antenna is anantenna which radiates the power in a narrow beam along a certain angleand directed to a certain area or receive antenna. Some embodiments ofthe invention use directional antennas that provide a large gain intheir favored direction. Some embodiments use a group of antennae (anantenna array) arranged to provide a large gain in a favored direction.

FIG. 2 conceptually illustrates an overview of a system 200 of someembodiments of the invention where the slave does not have a battery.The master 205 is the bigger system component with a good power source215 (e.g. AC or a good battery life), whereas the slaves 210 (only oneis shown for simplicity) have limited sources of power (e.g. limitedbattery or no battery). Example master devices are a car, PC, laptop,cell phone, digital/video camera, or multimedia device such as an IPod.The slave device could be any non-battery device (e.g. memory stick ormemory device) or DC or battery operated device. Some examples of thelatter are laptop, cell phone, PDA, wireless headsets, wireless mouse,wireless keyboard, pager, digital/video camera, external hard drive,toy, electronic book readers, sensor, CD/DVD/cassette/MP-3 player,toothbrush, lighting devices, electronic appliances, or a car (e.g., anelectric car). Even AC powered devices in some embodiments use thissystem as a backup power system in case AC power goes off. Thus, abattery operated master could power up an AC powered device thattemporarily has lost its AC power source.

In some embodiments, the master is just a dedicated charging device anddoes not communicate with the slaves other than for charging. The masterhas a power source 215 such as AC or battery. The power source powersthe master's RF transceiver 220, processing module 225 and network card230 which are all connected to a bus 235. Although the term transceiver(which implies a module with shared circuitry for a transmitter andreceiver) is used in FIG. 2 and some of the following figures, theinvention is not restricted to transceivers. Some embodiments usetransmitter-receiver modules (which has transmitter and receiver in thesame housing without common circuitry) while other embodiments useseparate transmitter and receiver modules. The master may be connectedto a network 240 such as the Internet through its network card 230 orthrough a wireless connection. The master has a high gain antenna 245.The master's RF transceiver 220 uses the antenna 245 to shoot itsfocused beam to the slave to power up the slave. This power up RF waveis not modulated since it is used for power generation and not datatransmission. The antenna in some embodiments is comprised ofsub-elements such that through different phases and amplitudes themaster uses beam steering to change the angle of the beam as describedby reference to FIGS. 4 and 8 below. The battery-less slave 210 of FIG.2 also has a directional antenna 250 that is connected to a powergenerator component 255. The power generator provides power from thereceived radio frequency signals. The energy from the master's RFtransmission is converted by this component to a supply voltage (notshown) and is stored in a capacitor (not shown). This supply voltage isthen provided to the slave's transceiver 260 and processing module 265to power them up. The slave may optionally have a network card (notshown) which is also powered up with this supply voltage. The slave usesthe network card or its RF transceiver to connect to a network. Once theslave is powered up it is ready to communicate with the master. Themaster then sends commands (e.g. read from slave's memory, write toslave's memory) to the slave in some embodiments. The slave sendsreceive acknowledgments to the master and responds to commands. Forexample, in response to a read command the slave retains data (text,images, audio, and video). The slave also sends status information tothe master such as “I am this device”, “I have data”, “I need to becharged”, “My battery level is 50%”, etc in some embodiments. The rangeof this system is not limited by the radio since the radio requireslower sensitivity and can handle low input signals. The terms RF-basedmaster or RF beam master are interchangeably used in this specificationto refer to a master that uses an RF beam to charge the slaves.

The power generator in FIG. 2 is used to generate a voltage supply andstore it in a capacitor. FIG. 3 conceptually illustrates an alternativesystem 300 of some embodiments of the invention where the slave has abattery. The master components are similar to the components shown inFIG. 2. In these embodiments, the slave battery 315 is charged by a highfrequency directional RF beam from a master device 305. The battery isthen used for powering the slave 310 for communication. In FIG. 3 slave310 uses a low frequency low bandwidth control channel 320 to adjust theposition of a switch 325. In FIG. 3 slave 310 includes a control module320 that uses a low frequency low bandwidth control channel to adjustthe position of a switch 325 and set whether to use the energy capturedby the power generator 330 to power up the device, charge the battery315, or both. The control channel 320 could use a simple modulationmethod such as amplitude modulation (AM), frequency modulation (FM),phase, and quadrature amplitude modulation (QAM), rather than complexwireless modulation techniques (e.g. Orthogonal frequency-divisionmultiplexing (OFDM)). These simple modulation schemes require lesscomplex hardware and processing and are optimal for low-speed data.Either the slave, or the master, or both in combination can decidewhether the slave should communicate at first or not. For example, theslave looks at its battery, decides how much life it has, and thendetermines whether to charge, communicate, or do both in someembodiments. Feedback mechanisms could be used to dynamically improvethe system. For instance, if the slave sends data to the master and themaster determines that the data from the slave is bad quality then themaster in some embodiments uses the control channel to tell the slave tonot use any of the received energy for charging and instead use all ofit for live communication only. There are several possible strategiesfor slave power status and master charging, eight of which were listedin the previous section titled “Charging and Communication Strategies”.

FIG. 4 illustrates a more detailed diagram of the embodiments shown inFIGS. 2 and 3. The master 405 has a power source 410 such as AC power(which is rectified and regulated with an adaptor), battery, or someother power generating device (e.g. induction from another source asdescribed below by reference to FIG. 20). The master's RF transceiverradio has a transmitter (Tx) 415, a receiver (Rx) 420, and a digitalbaseband processing unit 425. The transmitter includes a Digital toAnalog Converter (DAC) (not shown). RF transmissions for power are notmodulated, whereas data transmissions use modulation and optionallycoding. The receiver includes an Analog to Digital Converter (ADC) (notshown). The digital baseband unit 425 communicates with a processingmodule 430 that includes a digital signal processing unit 435, aprocessor 440 and memory 445. The transceiver's transmitter and receiveruse a duplexer 455 that allows bi-directional communication over asingle channel and antenna. Some embodiments include an optionalattenuator 450 which is placed in front of the receiver. This protectsthe receiver from being overloaded by the transmitter or by other largeincoming signals. The attenuator also allows the receiver to receivewhen the transmitter transmits. The attenuator attenuates the entiresignal and is like an all-pass filter. Alternatively, instead of theattenuator some embodiments include frequency-selective filter toprotect the radio. FIG. 4 shows a general case where the antenna hassub-elements 442 that enable steering of the beam. Each antennasub-element is effectively a separate antenna and throughout thisspecification the term antenna and antenna sub-element will be usedinterchangeably. In FIG. 4 a beam-forming unit (or beam former) 453 isplaced before the duplexer 455. In other embodiments the beam-formingunit is placed after the duplexer. The beam former takes the output ofthe transmitter (Tx) and generates different phase and amplitudes foreach of the antenna sub-elements in order to steer the beam. Likewise,on the receive side the beam-former takes multiple receive signals fromeach antenna sub-element and combines them with multiplephases/amplitudes and provides the output to the receiver (Rx). In yetother embodiments there is not an explicit beam-forming component andthe beam-forming function is integrated into the transmitter (Tx) andreceiver (Rx) where they generate the phase and amplitudes forbeam-forming. The master's beam former is used to focus the transmitpower on the slave's antenna for optimum power transfer, while theslave's beam former is used mostly for communication.

In some embodiments, the master and slave use a frequency hoppingmechanism in order to avoid unauthorized slave devices from using themaster as a charger. For example, a particular company that producesslave devices (cell phones, IPod, laptops, etc) and chargers for themcould include a frequency hopping mechanism that both the slave and themaster devices from that company would know about. For instance, amaster detects and charges a slave using frequency f1 and after anelapsed time T1 the master's frequency is changed to f2 and the slavewould also know that it has to change to that frequency. After a furtherelapsed time of T2 the master's frequency is changed to f3 and the slavechanges too, etc. An unauthorized slave would not know how to change itsfrequency with time and as a result of the mismatch between itsfrequency and that of the master then it will not receive a lot of powerfrom the master. In FIG. 4, the baseband of the transmitter has afrequency hopping unit 460 that generates the clock 463 frequency forthe transmitter and receiver. In some embodiments, the transmitter andreceiver have the same frequencies while in other embodiments they havedifferent frequencies. In some embodiments the master would have aninterface where the user programs the frequency hopping algorithm anddownloads it to certain slaves such that the master could only chargeand communicate with slave devices that the user chooses. In someembodiments, the master performs time hopping. With time hopping themaster transmits at different times based on a known sequence betweenthe master and the slaves. The slaves look at incoming energy at thoseknown specific time intervals. In some embodiment, during each time hopthe frequency also changes in order to separate the slaves further.

The slave 470 in FIG. 4 has components similar to the master 405, themain difference is the power generation component 473 which will bediscussed in more detail below. The antenna elements 499 of the slavereceive the RF waves from the master. The energy from the master'snon-modulated RF transmission is converted by the slave's powergenerator to a supply voltage, Vdd, and is stored in capacitor C 475.This supply voltage is then fed to a voltage converter 477 whose outputprovides different voltage levels as required by the different slavemodules. The outputs from the voltage converter are then provided to theslave's transceiver 480 and processing modules 483 (and networkingmodule if it has one) and power them up. It is also possible thatdifferent modules have different Vdd values. If the slave is a sensorthe processing module may also optionally have a sensor and associatedcircuitry. Again, an optional attenuator 485 may be placed in front ofthe slave's receiver to protect it from being overloaded by thetransmitter or by other large incoming signals. The attenuator alsoallows the receiver to receive when the transmitter transmits. Afrequency-selective filter 487 is also used in some embodiments toprotect the radio. For instance, when two different frequencies are usedfor power generation and communication, the filter may be chosen suchthat it rejects the power frequency but allows the communicationsfrequency. Like the master, the slave also has beam forming 488 forsteering its beam, and frequency hopping 481 for limiting power transferto authorized slaves.

The calibration block 490 calibrates and tunes each antenna to maximizepower. It matches the impedance of each antenna with its rectifier. Theconfiguration block 492 controls the calibration block. Since theseblocks also need power, some embodiments initially power up a smallportion of the circuits. For instance, one or more of the antennasub-elements receive the RF power. The signal is then rectified (by therectifier 493), the power absorbed, and converted to a supply voltage,Vdd, for a small power absorber, and stored it in a small capacitor 494.This supply voltage is then provided to the slave's configuration 492and calibration blocks 490. The calibration block calibrates thematching of each antenna or frequency tunes to the master's frequencyeach of the antennas in some embodiments. The power generator has arectifier 495 for each of the antenna sub-element 499 signals. A summer471 then sums the output of all rectifiers 495. The configuration blockmonitors each antenna signal (before the power generator's rectifiers asshown in FIG. 4, although it could also monitor after the rectifiers).The configuration block then controls the calibration block to changethe antenna timing in order to maximize the signals. Once the powergenerator's Vdd reaches a pre-set level the configuration block uses aswitch 496 to provide the power to the rest of the system, such as theprocessing module 483, the RF transceiver 480, and any other modules(e.g. network card module if there is one in the slave). If the slavehas a battery 497 the switch is also used in some embodiments to enablebattery charging only, or enable battery charging and power-up togetherso that the slave is able to communicate while the battery is charging.The battery block has associated circuitry to measure its parameters andprevent overcharging. The battery block also includes a regulator and abattery charger unit in some embodiments. For most consumer electronicsdevices these changes could be incorporated into their battery packs.The slave in some embodiments also has a power management module 498which performs functions to increase the battery life of the device. Forinstance, the power management unit in some embodiments puts certainmodules in sleep or idle mode, and/or use frequency and voltage scalingto reduce power consumptions.

The calibration block also has a backscattering transceiver in someembodiments. If the RF transceiver is not powered on and the slave needsto communicate back to the master the calibration block uses antennamodulation in the form of backscattering (e.g. acknowledgement that itreceived data, or transmission of information like MAC ID, name, etc.).The received signals at the slave also include control information,where the master uses a control channel to inform the slaves what to do.The slave's control channel will demodulate and extract the commands forthe slave to execute. Control information also includes read commands,write commands, turn on and off commands for the RF transceiver,scheduling for sending and receiving data, configuration and calibrationof software radios for different standards.

In some embodiments, the slave stores identifying information aboutmasters (or networked servers) that are authorized to charge the slave,such as the masters' media access control address (MAC ID), network IPaddress, name, serial number, product name and manufacturer,capabilities, etc. This information is stored in its memory 474 or inits configuration block 492. The slave requests identifying informationfrom the master or the network server 135. The master (or the networkserver) is also proactive in some embodiments and sends its identifyinginformation to the slave. Identifying information about the masters isstored in a networked database 150 in some embodiments. The slave insome embodiments checks the master's information with its authorizedlist and if there is not a match the configuration block 492 controlsthe switch 496 so power does not reach some or all of its circuitsand/or battery.

The charging application is for distances of 1 meter or less. The energyefficiency of the system is the efficiency of the transmitter (DC to RFconversion) and the receiver (RF to DC conversion). The path loss isproportional to the inverse of the distance squared and inverse of thefrequency squared. For instance at 60 GHz, at a distance of 1 meter thepath loss is 64 dB. Thus, if the master transmits 100 mW the receivergets about 20 dBm, since there is little loss. The conversion of thisreceived RF to DC has about 10-20% efficiency, which translates into10-20 mW.

This method is used both to charge the slave device and to send data toit in some embodiments. The higher carrier signal frequency enables theuse of much smaller antennas. Because the antennas are small, in someembodiments the master devices (and even slave devices) have a number ofantennas so that orientation with the charger can vary. When the slavehas directional antenna, power efficiency is greatly enhanced. Powerefficiency is also most optimal when the antenna of the master and slaveare pointing directly towards each other.

In some embodiments, the master is a device (e.g. a PC) that has ACpower or has a number of batteries and the slave (e.g. cell phone) has abattery that may require charging. Charging is either initiated by theslave or by the master. For example, the user places the slave near themaster and presses a button on either the master or the slave toinitiate charging (or charging is initiated after the master polls theslave). The slave makes a digital request to the master to be charged.Each antenna on the master receives a DC current. However, the antennathat is pointing to the slave device's antenna will receive the largestcurrent. Each of the master's antennas effectively acts as a USB portsince the antennas are used for communication as well as charging. Ifthere are more than one slave then the master in some embodiments powersup all of them if need be and communicate with all of them usingmultiplexing. This eliminates the need for the master device to havemultiple USB ports. Specifically, currently for each device there is aneed for one USB port. For example, there is one for the mouse, one forthe keyboard, one for a memory stick, etc. Using the embodiments of thecurrent invention, they can all share the same wireless communicationlink with multiplexing for communication. For a USB type slave devicethat has no battery the master just acts like a remote battery so thatthe slave is able to communicate. For a more powerful slave device, suchas a cell phone, the master acts like a charger and a communicationdevice. If the slave has sensors (e.g. temperature, gyrator, pressure,and heart monitor) with electronic circuitry then they are powered up bythe master, perform their sensing functions and communicate their datato the master, a network server, or some other device. In someembodiments, either or both the master and the slave have a touch screenand/or keyboard. For example, the master's keyboard is used for inputand its touch screen is used for both input and output. Input data isthen communicated to the slave. Likewise, when the slave has a keyboardand/or touch screen, input data is displayed on the slave's screen andis optionally communicated to the master.

FIG. 5 conceptually illustrates a process 500 for master-slave chargingand communication in some embodiments of the invention. The exactsequence of events and command/information flows depends on whether themaster or the slave initiates the communications. The commands aremostly transmitted over the control channel that uses a simplermodulation (e.g. AM, FM) than the data channel (although someembodiments send commands over the data channel). Channel coding is anoptional step prior to modulation to improve data transmission andrecovery under noisy conditions.

As shown in FIG. 5, the master powers-up (at 505) the slave. The powerup is initiated by either the master or by the slave. For instance: (a)the slave makes a request for power (e.g. user presses a button on theslave for power or a low power slave automatically requests to becharged provided it has a battery charge, (b) the slave does not havecharge, but the master polls the slave (either regularly or by manuallypressing a button on the master) and then the slave requests power (c)the master detects the slave when it gets close to it, polls it and thenthe slave requests power. In some embodiments, when the master has ACpower, the master goes to discovery mode where it polls frequently andgoes off. In some embodiments, when a master has battery, the mastergoes to discovery mode and if it finds no slaves it slowly backs off(for instance going from 1 minute polling interval to 2 minute pollinginterval, then to 3 minute polling interval, etc.)

Next, slave sends (at 510) request for power. Master receives theslave's request for power, demodulates (at 515) it, and in responsegenerates (at 520) an RF wave. In some implementations the masterautomatically charges the slave or have some charging rules (e.g. ifbattery charge of slave is less than 50% then charge slaveautomatically). In these embodiments, operations 510 and 515 areskipped.

The slave receives the RF wave from the master, and the slave's powergenerator component converts the RF wave energy to a supply voltage.This is used (at 525) to power-up the slave, charge its battery if ithas one, or both. The slave then transmits (at 530) information aboutitself (or its surrounding if it is a sensor) or makes (at 530)requests. The slave optionally codes the information before modulationin some embodiments. For instance, the slave transmits information suchas “I am this particular device”, “I have data to be read”, “I need tobe charged”, etc. Active slaves (e.g. cell phones or toys withbatteries) use the power of the master instead of their own battery insome embodiments.

The master then receives and demodulates (at 535) the slave'sinformation/request (anti decodes if necessary). The master's processingmodule determines (at 540) whether the master continues the session.When the master determines that the session shalt not be continued, thesession is stopped (at 545). When the session continues, the master'sprocessing module generates (at 550) commands (e.g. read from memory,write to memory, put into idle energy state, or other specific commands)which are optionally coded and modulated by the master's transceiver andtransmitted.

The slave receives the roaster's signal, demodulates (at 555) thereceived signal, and decodes the signal if necessary. Next, the slaveexecutes (at 560) the command (e.g. read, write, idle, specificcommand). In some embodiments, the slave optionally codes (at 565)status information. The slave then modulates (at 565) and transmits (at565) status information or other requests back to the master (e.g. theread data, write successful status, command successful status,acknowledgements). The master demodulates (at 535) the slave'stransmission and its processing module determines if it continues thesession (decision to continue is possibly based on the information sentby the slave). In some embodiments, the slave's status transmissioninformation includes low battery/charge information or requests forcharging (at 565), and the master's processing module processes theinformation/requests and charges the slave (at 535).

FIG. 6 conceptually illustrates a master with different transmitters forpower generation and communication in some embodiments of the invention.One transmitter of each type is shown for simplicity. As shown, themaster 605 includes two separate transmitters (possibly with differentfrequencies) that are used for power generation and communication. Thepower transmitter 610 performs the function of a dedicated battery forthe slaves. In some embodiments the power transmitter has narrowbandwidth but is high power compared to the communication transmitter ormore wideband transmitters. A more focused antenna beam and a higherpower transmitter increase the power transfer to the slave. Thecommunication transmitter 615 and the power transmitter 610 in someembodiments have different frequencies from while in some embodimentsthe two transmitters have the same frequencies. In some embodiments, thefrequencies are Federal Communications Commission (FCC) approved. Theattenuator 620 prevents the transmitter from overloading the receiver630 and allows the receiver to receive when the communicationtransmitter transmits. The transceiver's transmitter and receiver use aduplexer 650 that allows bi-directional communication over a singlechannel and antenna. In some embodiments, the filter 625 is chosen suchthat it rejects the power frequency but allows the communicationfrequency. A duplexer or combiner/de-combiner 635 is used with a singleantenna 640.

FIG. 7 conceptually illustrates a master and a slave that each includesseparate antennas/transceivers for power generation and forcommunication in some embodiments of the invention. For simplicity, onlyone antenna/transceiver of each type is shown. As shown, the master 705includes an antenna 715 and a transceiver 720 for power generation. Themaster also includes an antenna 725 and a transceiver 730 forcommunication. Similarly, the slave 710 includes an antenna 735 and atransceiver 740 for power generation and an antenna 745 and atransceiver 750 for communication. Thus, the antenna used for powergeneration has a directional focused beam pattern and is used with ahigh frequency to generate power at the slave. The control channel runson the power transmitter's channel in some embodiments while the controlchannel runs on the communication transmitter's channel in otherembodiments.

FIG. 8 conceptually illustrates a master in some embodiments that usesbeam steering to change the direction of the beam when the slave is notdirectly in front of its beam of the invention. As shown, the master 805has four antennas 810-825. Slave A 830 is directly in front of antenna810 and receives most of the energy of the RF beam of that antennawithout any steering of the beam. Slave B 835, however, is located at anangle to all of the master's antenna beams. The efficiency of the systemis less when the slave is positioned at an angle to the main beam'santenna. However, antenna 810 and 815 use beam steering to target theantenna of slave B 835.

Furthermore, using both antennas 810 and 815 improves efficiency becausethe power generator of slave B 835 uses the energy simultaneouslyreceived from both antennas to generate a supply voltage. Once slave B835 is powered up it uses one of the antennas for communication (e.g.the antenna with the more reliable signal or the stronger signal). Asdescribed by reference to FIG. 1 above, more than one master (eithersimultaneously or separately) charge a single slave (e.g. masters B 115and C 120 charge slave 6 in FIG. 1) or several slaves in someembodiments. In some embodiments the masters communicate with each otheror alternatively a network server or remote user configures them tochange their beam steering and other system parameters such that theymaximize power transfer to a single slave or a plurality of slaves.

FIG. 9 conceptually illustrates a multi-antenna RF master in someembodiments of the invention that has a non-conductive spacer material(e.g., plastic) in front of its antenna 915. This spacer 910 is used toenable the slave 920 to sit on it or get close to it. This creates aseparation distance of several wavelengths between the master 905antennas 915 and the slave 920 antennas 940 so that RF is used forcharging. For instance, for a single antenna a separation of two or morewavelengths is needed. For multiple antennas more wavelengths arerequired, the number of which increases with the number of antennas foroptimal beam forming. This could for example be used for wirelesscharging and wireless USB communication (since each of the master'santennas effectively acts as a USB port that is used for communicationas well as charging). Without the separator the slave and the mastercould be too close to each other because of the short wavelengths ofhigh frequency RF. If the master and the slave are too close to eachother, some embodiments use induction charging instead of RF charging.Although FIG. 9 shows one slave antenna and several master antennas, indifferent embodiments of the invention either the slave or the masterhas one antenna, many antennas, or one or more antennas withsub-elements. In some embodiments, a slave has a non-conductive spacermaterial (e.g., plastic) in front of its antenna 940 (not shown) toenable the slave to sit on the master or come close to it.

III. Charging with Induction

FIG. 10 conceptually illustrates a master that uses induction to chargeand communicate with a slave in some embodiments of the invention. Themaster 1005 supplies its primary coil 1010 with an alternating current,thereby creating an AC magnetic held. This magnetic field generates avoltage across the receiver's coil 1015, which is rectified and smoothedwith capacitors (not shown), and used for charging and communication.The power source for the master in different embodiments is an AC sourcethat is converted to DC by an adaptor 1070, a battery, or othermechanisms (e.g. induction from another master induction charger). Aselection switch 1060 in some embodiments selects amongst the differentpower source options and provides the Vdd to the master's powertransmitter. In some embodiments, the power transmitter 1020 uses aPhase Lock loop (PLL) 1025 that uses a crystal's frequency to synthesizea new frequency. Alternatively, the power generator in some embodimentsuses a Direct Digital Frequency Synthesizer (DDFS). The powertransmitter then uses a Power Amplifier (PA) 1030 to drive its coil. Inthe embodiments shown in this figure and the other following figuresthat illustrate induction, one end of the coil is connected to the PAwith the other end grounded. However, some embodiments use adifferential coil where the two ends of the coil are connected to the +and − input of the PA. If no modulation is used, the transmitted energyis used to charge a slave through induction of the slave's coil. But ifthe transmitted signal is modulated (amplitude, frequency, phase or acombination) the signal is also used to transmit data as well as powerin some embodiments. In some embodiments, when the transmitter is notsending data it just charges the slave 1035 or the slave communicatesback on the same frequency or a close frequency. The slaves usebackscattering to send information to the master. When the master is inreceiving mode, the signal coming from its coil to the receiver isdetected. The signal level is adjusted by an attenuator 1040 and a poweramplifier 1045. The detector 1050 then demodulates the signal. Theresulting data is then passed on to the processing module 1055 that hasa digital signal processing unit, a processor and memory, as well as anetworking card (not shown).

FIG. 11 conceptually illustrates a master in some embodiments of theinvention that uses the power transmitter for charging, and a separatetransmitter for data transmission. Other components of FIG. 11 aresimilar to FIG. 10. In some embodiments this data transmitter 1110functions similar to Near Field Communication (NFC) since NFC also usesinduction over very short distances for communication. FIG. 11 shows twoseparate coils 1115 and 1120 for the power transmitter and the datatransmitter respectively. However, some embodiments have one physicalcoil used for both transmitters, where the power transmitter uses theentire coil and the data transmitter uses all or a smaller section ofthe same coil. This has the advantage of reducing the number of coils.

FIGS. 10 and 11 show the master with one coil per transmitter. However,in some embodiments the master has a number of coils so that the mastercharges and communicates with several slaves, or is able to transmitmore power. For instance, networked masters in some embodiments havecoils that are built-in to conference room tables and marked so thatmeeting participants can wirelessly charge their devices, connect toeach other or to the Intranet/Internet, and transmit/receive information(this also applies to RF beam chargers where RF beam chargers such asmaster devices shown in FIGS. 2-4 and 6-9 are built-in to conferenceroom tables and marked so that users can wirelessly charge theirdevices, connect to each other, connect to a networked server or to theIntranet/Internet, and transmit/receive information). Alternatively, themaster has the form factor of a light weight pad that is used at home,in the car, on the go, or at work to charge and communicate with anumber of devices. Such multi-coil or RF beam masters, tables or padsare smarter in some embodiments and have additional dedicated functionsthat resemble a small computer. For instance, in some embodiments theyhave a credit card reader so that users of slaves are not only able tocharge their devices but also make payment transactions. Thus, a subsetof the coils (or antennas) is dedicated to interface with near fieldcommunication (NFC) devices. For example, in some embodiments of theinvention phones with NFC capabilities are not only charged but they arealso used for contactless payment so that the user places the phone nearthose coils (or RF beams of a master in the case of RF-based master) inorder to get authenticated and transmit payment information to a securedserver on the Internet. Alternatively, credit cards in some embodimentshave a chip so that they transmit their information to the masterdevice. The users may also choose to enter the payment informationmanually if they choose to do so. Some of the master's coils (or RF beamof a master in the case of RF-based master) are dedicated and optimizedfor communication, instead of having all coils be responsible forcharging and communication in some embodiments. Likewise, some coils arededicated and optimized for charging in some embodiments. Thesemulti-coil masters, tables or light-weight portable pads use either awireline or wireless connection to connect to the Internet, or anIntranet. They use their connection in some embodiments to communicatewith a fax/printer for faxing and printing functions. In someembodiments these multi-coil masters, tables or light-weight portablepads charge a cell phone and then use the cell phone's networkingfunctions (cellular, WiFi, Bluetooth®) to connect to anIntranet/Internet/server for authentication, web browsing, securetransaction, printing/faxing, etc. In other embodiments a tablet device(such as an IPad®) has a light-weight pad attached to it such that thetablet is wirelessly charged and then become a wireless charger tocharge a cell phone. In other embodiments multi-coil masters, tables orlight-weight portable pads have photocells to get charged and thencharge other devices such as cell phones wirelessly. In yet otherembodiments light-weight portable pads have USG or other types of portsfor charging and communicating with other devices in a car (both wiredor wirelessly). Such pads also have built-in GPS and Wireless LANfunctionality in some embodiments.

If a master device has an array of n coils all n coils are used tocharge and communicate with one slave in some embodiments, or all ncoils are used for a number of slaves in some embodiments. The samechannel is used for power transfer and then communication in someembodiments. In some embodiments, every coil has a built-in transceiver.In other embodiments a subset of the coils has built-in transceivers.During a calibration and configuration stage the master and the slaveexchange information in order to get to know each other. For example,the master instructs which slaves should be on or off in someembodiments. Frequency and time hopping are coordinated between themaster and the slaves in some embodiments for selection amongst aplurality of slaves, as well as additional security. Thus, the mastertransmits configuration information to the slaves, such as coilfrequency and hopping algorithms. The slaves send back acknowledgementsor the data to make sure they received it correctly. The slaves alsotransmit their voltage and current requirements to the master in someembodiments. If a coil at position P at time t has frequency f then itcan be represented by (f, t, P). Frequency hopping is a method whereeach coil in the matrix of coils is driven by a different frequency f atdifferent time periods. For example coil 1 has frequency f1 for t1seconds, frequency f2 for t2 seconds, etc. Time hopping is the processwhere each coil in the matrix is turned on and off at different timeperiods.

FIG. 12 conceptually illustrates a master 1205 that has a powertransmitter for each of its coils 1210 in some embodiments of theinvention. Thus, each coil (or a subset of the coils) has a differentfrequency to implement frequency hopping. In some embodiments, themaster 1205 also makes the power on each transmitter 1215 on and off tohave time hopping. Other components of the master (which in differentembodiments are similar to components shown in FIG. 10, 11, or 20, or21) are not shown for simplicity. FIG. 13 conceptually illustrates amaster in some embodiments with coils 1310 that have the same frequencyand a multiplexer 1315 to activate coils at different times. The PLL1320 in some embodiments also change the frequency if the master wantsto have both frequency and time hopping. Other components of the masterare not shown for simplicity.

FIG. 14 conceptually illustrates induction in some embodiments betweenthe master and the slave by using more than one coil on the master orthe slave in order to increase power and communication efficiency. Othercomponents of the master (which in different embodiments are similar tocomponents shown in FIG. 10, 11, or 20, or 21) are not shown forsimplicity. As shown, the master 1405 includes four coils 1410-1425,slave A 1430 includes two coils 1435-1440, and slave B 1445 includes onecoil 1450. As shown in the example of FIG. 14, slave A's two coils1435-1440 couple with one end 1410 on the master 1405. Likewise, themaster's coils 1415-1425 couple with slave B's one coil 1450. In thegeneral case in some embodiments X coils on the master couple with Ycoils on the slave. In some embodiments, coupled master coils such as1415-1425 have the same frequency. In other embodiments, the coils havedifferent frequencies f1, f2 and f3. In these embodiments, thefrequencies are within the bandwidth of the transformer system so thatthey couple and their power is added together.

In some embodiments, both the master and the slave have a matrix ofcoils. Different embodiments arrange the coils differently, for instancematrix of coils are arranged in 1D (one line), 2D (a plane), or 3D(multiple planes covering a volume). Some embodiments arrange the coilsin different patterns (rectangular grid, triangular grid, circular grid,hexagonal grid, irregular grid, etc). The master then requests theslave's coil patterns. The slave sends it coil pattern to the master.The master then activates a subset of its coils in order to generate atransmit coil pattern that transfers maximum power to the slave. Theslave then informs the master how much power each of its coils receives.The master then changes it's transmit coil pattern in order to optimizepower transfer to the slave. In some embodiments this process isrepeated until optimum power transfer is achieved.

FIG. 15 conceptually illustrates a process 1500 of some embodiments ofthe invention to change a master device's coil pattern in someembodiments of the invention. As shown, process 1500 receives (at 1505)the slave's coil pattern. Next, the process activates (at 1510) some orall of master coils in order to transmit maximum induction power to thesalve's coils.

Next, the process receives (at 1515) information regarding the amount ofpower each slave coil receives. In different embodiments, the masterreceives this information from the slave (1) using RFID andbackscattering techniques, (2) through RP data transmission from theslave's RF antennas, or (3) through data transmission from one or moreof the slave's coils.

The process then determines (at 1520) whether on optimized powertransfer is achieved (e.g., when the rate of power transfer satisfies acertain threshold). When the process determines that optimized powertransfer is achieved, the process continues (at 1530) induction powertransfer using the same coil pattern. The power transfer continues untila set of predetermined criteria (e.g., a certain amount of time elapsesa signal is received from the slave, slave's coil impedance changes,etc.). The process then exits.

Otherwise, when the process determines that optimized power transfer isnot achieved, the process changes (at 1530) the transmit coil pattern.The process then proceeds to 1515 which was described above.

FIG. 16 conceptually illustrates a multi-coil slave with inductioncharging in some embodiments of the invention. FIG. 16 shows a generaldiagram of a slave device 1605 that has M coils 1610. While in someembodiments slave devices have one coil in other embodiment (such as theembodiment shown in FIG. 16) have more than one coil. As shown, a Pnumber of coils are used for power absorption and an N number of coilsare used for data communication, where P≤M and N≤M and P+N=M. The systemis reconfigurable so that the numbers P and N are changed so thatdifferent numbers of coils are used for power and data communication asneeded. When a slave comes close to a master the master detects a changein its load. The master then gives power to the slave. The AC magneticfields generated by the primary coils of the master charger generatevoltages across the coils of the slave. The power harvester 1615rectifies and smoothes these voltages and its output are used forcharging and power. As shown, the power harvester 1615 is connected tothe coils through the front-end switching block 1690. Initially, a smallportion of the circuits, such as the calibration and configuration block1620, are turned on with DC power from the power harvester. Then themaster uses data modulation or some other modulation method to sendconfiguration information to the slave's calibration and configurationblock. This configuration information includes one or more of themaster's frequency, master's data and modulation method, and master'sidentifying information. The slave's calibration and configuration blockmonitors 1620 the signal before or after the power harvester 1615 anduses the configuration information together with tuning, calibration,and impedance matching of each coil with its rectifier (not shown) tomaximize the signal. After the signal is maximized then the slave'scalibration and configuration block adjusts a switch 1625 so that powerbecomes available for the battery 1630 (if the slave has one) and/orother circuits such as the data transceiver 1635 and the processingmodule 1640. The battery block 1630 has associated circuitry to measureits parameters and prevent overcharging. The battery block 1630 alsoincludes a regulator and a battery charger unit (not shown) in someembodiments. A voltage converter 1650 is used to provide differentvoltage levels as required by the different slave modules. The slave insome embodiments also has a power management module 1655 to increase thebattery life of the device.

In some embodiments the slave stores identifying information aboutmasters (or networked servers) that are authorized to charge it. This isstored either in the slave's calibration and configuration block or theslave's memory (not shown). The slave checks the configurationinformation sent from the master to the slave for the master'sidentifying information. If the information is not included the slaverequests it. The slave then checks this information with the authorizedlist and if there is not a match the slave's calibration andconfiguration block disables charging and/or power-up by controlling theposition of the switch.

The slave's data transceiver 1635 is reconfigurable so that Ktransmitters 1665 and P receivers 1670 are used. For instance, more thanone transmitter in some embodiments is used to drive a single coil.Likewise, more than one receiver in some embodiments is used to receivefrom a single coil. In some embodiments, a master device has a similarconfiguration. If the slave is only charging its battery, once thebattery is charged the slave in some embodiments disables its coil(s) orchanges its impedance so that the master knows the slave does not needmore power for charging. During data communication the load modulationunit 1660 modulates the load for the coils. When the load on the slave'scoils changes then the system acts like a transformer and the sameeffect is shown on the transmitter's coils through coupling. The changesrequired to implement this system can be incorporated into the batterypack of most electronics systems (conventional battery packs typicallyinclude rechargeable batteries that use AC power adapters. These batterypacks could be changed to include the components of FIG. 16 instead).

The slave in some embodiments optionally has sensors 1675 withelectronic circuitry. Once the slave is powered up the sensors performtheir sensing functions and communicate their data to the inductioncharger, another master, or a network server. Some examples of sensorsare temperature, gyrator, pressure, and heart monitor. The master andthe slave in some embodiments optionally have a touch screen and/orkeyboard for entering data which is displayed on the screen and/orcommunicated, respectively, to the slave and the master.

FIG. 17 conceptually illustrates a process 1700 for reconfiguring coilsof a slave device in some embodiments of the invention. As shown, theslave optionally receives (at 1705) induction power for a certain periodof time from the master to power up some or all of the slave'scircuitries. In some embodiments, when the slave initially has more thana certain amount of power, operation 1705 is skipped.

Next, the process receives (at 1710) configuration information from themaster. The master configuration information includes one or more of themaster's operating parameters such as the operating wirelesscommunication frequency of the master (which is used for communicationbetween the master and slave), master's data and modulation method, andmaster's identifying information. The process then reconfigures (at1715) the slave's coils by using the received configuration informationand one or more tuning, calibration, and impedance matching to maximizethe received induction power. Coarse calibration and fine tuning areperformed in some embodiments to ensure that all elements on the masterand slave have the same frequency and are tuned for it. Likewise,impedance matching is performed in some embodiments such that the masterand the slave are matched for communication. The process then receives(at 1720) induction power from the master device until the generatedpower in the slave reaches a certain threshold. The process then exits.

FIG. 18 conceptually illustrates a process 1800 for terminating powergeneration in the slave in some embodiments of the invention. As shown,the process receives (at 1800) power through the induction. Next, theprocess determines whether enough power is generated to satisfy acertain threshold. For instance, the process determines whether abattery or a capacitor in the slave is charged to a certain voltagelevel.

When the generated power does satisfy the threshold, the processproceeds to 1805 to continue receiving power through induction.Otherwise, the process either disables the coils (e.g., by turn a switchon or off) or changes the coils impedances as a signal to the masterdevice to stop transmitting induction power. The process then exits.Some embodiments use a similar process to terminate generation of powerthrough conversation of RF energy using a similar process as process1800. In some of these embodiments, the slave's voltage converter 477 isdisconnected from the slave's power generator 473 antennas isdisconnected from the slave's power transceiver. In other embodiments,the slave's antennas 499 are turned off.

FIG. 19 conceptually illustrates a process 1900 for configuring theslave's coils for either power generation or data transmission in someembodiments of the invention. As shown, the process configures (at 1905)salve's coils to use some or all of the coils for receiving powerthrough induction and some or none of the coils for data transmission.

Next, the process receives (at 1910) power through induction at theslave's coils. Next, the process determines (at 1915) whether enoughpower is generated at the slave to satisfy a certain threshold. Forinstance, the process determines whether a battery or a capacitor in theslave is charged to a certain voltage level. When the generated powerhas not satisfied the threshold, the process proceeds to 1910 to receivemore induction power. Otherwise, the process reconfigures the coils thatare used for power generation and data transmission. For instance, whenthe power in slave reaches a maximum threshold, no coils are used forpower generation and some or all coils are used for data transmission.As another example, when the power reaches a certain threshold, thenumber of coils used for data transmission is increased and the numberof coils used for power generation is decreased. In this example, powergeneration through induction continues until the power level reaches amaximum threshold.

IV. Charging with Both RF and Induction in a Hybrid Configuration

Although the embodiments discussed by reference to FIGS. 1-19 describedmasters with either coils or RF antennas, the invention is notrestricted to these embodiments. Specifically, in some embodiments, boththe master and the slave have induction coils and RF antennas.

For instance, in some embodiments a master as shown in FIGS. 1-4 and 6-9in addition to RF antennas has coils and associated circuitry as shownto any of FIGS. 10-14. Also, in some embodiments a slave as shown inFIGS. 1-4 and 7 in addition to RF antennas has coils and associatedcircuitry as shown in FIGS. 12-16. Because the induction frequency andRF frequencies are far apart, each element (i.e. each master and slaveelement) is calibrated to have two different operating frequencies, onefor induction and one for RF.

FIG. 20 conceptually illustrates a hybrid system of some embodiments ofthe invention where the master uses an induction charger as a powersource to power itself and then uses a high frequency directional andfocused RF beam to power up one or more slave devices and communicatewith them. As shown, the master 2005 includes a rechargeable powersupply 2010, a power harvester 2015 and a coil 2020. The inductioncharger 2025 has a power source (AC power, battery, etc). The power isconnected to the induction charger's power transmitter 2035 (e.g., afteran AC source is converted to DC through an adaptor 2080), which isconnected to a primary coil 2040 with a reference ground point 2045.When the master's secondary coil is close to the charger's primary coilit receives power through inductance and its power harvester 2015charges the master's rechargeable power supply 2010. The master thenuses a high frequency directional RF beam to power up one or more slavedevices 2050 (or charge the slave device's battery if it has one) andcommunicates with it, as discussed by reference to FIG. 2-4. FIG. 20shows only one embodiment of induction charging, and there are otherimplementations and methods as discussed herein.

FIG. 21 conceptually illustrates a master in some embodiments of theinvention that acts as an induction charger and uses induction to chargethe slave before using its high frequency directional beam tocommunicate with the slave. The master 2105 has access to power (ACpower or battery). The master's power is connected to a powertransmitter 2110 that uses a multiplexer 2115 to power a matrix of coils2120. This is similar to the arrangement shown in FIG. 13, although eachcoil or a subset of coils may also have their own individual powertransmitters (as in FIG. 12). The slave 2125 includes a voltageconverter 2130, a rechargeable power supply 2135, a power harvester2140, a matrix of coils 2145 and other blocks of FIG. 16 that are notshown for simplicity (e.g. calibration and configuration block). Whenthe master's primary coils are close to the slave's coils the slavereceives power through inductance. The master then uses a high frequencydirectional RF beam to communicate with the slave. FIG. 21 shows onlyone embodiment of induction charging, and there are otherimplementations and methods as discussed herein.

FIG. 22 conceptually illustrates two slaves in some embodiments of theinvention that use the power of a master's coils to power up or chargetheir batteries and then communicate with each other using theircommunication transceivers. As shown, the two slaves 2205 and 2210 areplaced on or near a master 2215 induction charger. An example of such anembodiment (without any limitations) is: slave A 2205 is a cell phone,slave 2 2210 is a memory stick with data, and the master is a PC with aninduction pad. The two slaves use the power of the master's coils 2220to power-up or charge their batteries (not shown). The two slaves thenuse their RF transceiver (not shown) with directional beams (or anyother communication transceiver) to communicate directly with eachother. In other embodiments, the two slaves use the master and inductioncoupling to communicate with each other. For instance, where one or bothof the slaves do not have an RF communication transceiver and slave Awants to communicate with slave B, Slave A uses induction coupling withthe master to send its request for slave B to the master. The masteruses induction coupling to communicate that request to slave B. Slave Bthen uses induction coupling to reply to the master, and the master usesinduction coupling to forward the reply to slave A. In some embodimentsmore than two slaves get charged and communicate with each other. Anetwork server 2225 in some embodiments controls the master and theslaves through a network 2230.

The description so far has discussed induction charging and focused RFbeam as separate embodiments. FIG. 21 did discuss a master that usesinduction for charging and RF for communication. That role is reversedin some embodiments of the invention where RF is used for charging andinduction is used for communication. But it is possible to view the coiland the RF antennas as elements. In some embodiments one element isdesigned for the master, slave or both so that at low frequencies theelement is like a coil inductor and at high frequencies it is like anantenna. This means that at the same time one has RF power and inductionpower. Low frequencies mean big coils and high frequencies mean smallcoils. If the distance is far enough (e.g., more than 2-3 wavelengths)compared to the signal wavelength then waves are created and the elementis used for RF. If the distance is short then waves cannot be createdand it will be more like induction. So distance is used to select onemode or the mode is chosen automatically. In other embodiments themaster, slave or both have two different elements for differentdistances (one for short distances and one for far distances). In theseembodiments, the master does time multiplexing between the two or selectone over the other. This depends on the slave and whether it has eachelement for induction and RF antenna. If the master is charging andcommunicating with a group of antennas then the selection of inductionor RF depends on the configuration of the slaves as to which ones haveinduction, antenna or both.

FIG. 23 conceptually illustrates an element 2300 in some embodiments ofthe invention that is designed to be a single coil 2305 at lowfrequencies and a multiple antenna sub-elements 2310 at high frequencieswith beam forming capabilities. The element in some embodimentsphysically resembles a coil. In some embodiments, the length of the coilis much bigger than the size of antenna required for RF at highfrequencies. For instance in the frequency range of 50-60 GHz theelement is of the order of centimeters, whereas the antenna sub-elementsare of the order of millimeters. The element is divided into multiple RFantennas sub-elements and these multiple antenna sub-elements are usedto do beam forming. Each sub-element is of the order of half awavelength or less and operates at two separate frequencies, one lowerfrequency for the coil 2305 and one higher frequency for the antenna2310. Each sub-element has an associated port 2315 that is frequencydependent (e.g. a capacitor or an LC circuit) such that at highfrequency the sub-element acts as an antenna, but at low frequencies thesub-elements act as one connected coil. In FIG. 23, these ports 2315 arenot shown for the low frequency operation to emphasize that the element2300 acts as a single coil 2305 in low frequencies. All of thediscussions throughout this specification regarding slave and masterconfiguration and control and communication apply to embodiments thatuse the element shown in FIG. 23. For instance, in some embodiments, theelement is used in one or more of the master and slave devices shown inFIGS. 1-4, 6-14, 16, and 20-22. Also, one of the antennas 2300 is usedfor control and communication in some embodiments. In other embodiments,all antennas are used for control, communication and power. If lowfrequency and high frequency are used at the same time the communicationchannel in some embodiments is RF or induction or both.

V. Computer System

Many of the above-described processes and modules are implemented assoftware processes that are specified as a set of instructions recordedon a computer readable storage medium (also referred to as “computerreadable medium” or “machine readable medium”). These instructions areexecuted by one or more computational elements, such as one or moreprocessing units of one or more processors or other computationalelements like Application-Specific ICs (“ASIC”) and Field ProgrammableGate Arrays (“FPGA”). The execution of these instructions causes the setof computational elements to perform the actions indicated in theinstructions. Computer is meant in its broadest sense, and can includeany electronic device with a processor (e.g., moving scanner, mobiledevice, access point, etc.). Examples of computer readable mediainclude, but are not limited to, CD-ROMs, flash drives, RAM chips, harddrives, EPROMs, etc. The computer readable media does not includecarrier waves and/or electronic signals passing wirelessly or over wiredconnection.

In this specification, the term “software” includes firmware residing inread-only memory or applications stored in magnetic storage that can beread into memory for processing by one or more processors. Also, in someembodiments, multiple software inventions can be implemented as parts ofa larger program while remaining distinct software inventions. In someembodiments, multiple software inventions can also be implemented asseparate programs. Finally, any combination of separate programs thattogether implement a software invention described herein is within thescope of the invention. In some embodiments, the software programs wheninstalled to operate on one or more computer systems define one or morespecific machine implementations that execute and perform the operationsof the software programs.

FIG. 24 conceptually illustrates a computer system 2400 with which someembodiments of the invention are implemented. For example, the masters,slaves, network servers, access points, and processes described above byreference to FIGS. 1-23 may be at least partially implemented using setsof instructions that are run on the computer system 2400.

Such a computer system includes various types of computer readablemediums and interfaces for various other types of computer readablemediums. Computer system 2400 includes a bus 2410, at least oneprocessing unit (e.g., a processor) 2420, a system memory 2430, aread-only memory (ROM) 2440, a permanent storage device 2450, inputdevices 2470, output devices 2480, and a network connection 2490. Thecomponents of the computer system 2400 are electronic devices thatautomatically perform operations based on digital and/or analog inputsignals. The various examples of user inputs described above may be atleast partially implemented using sets of instructions that are run onthe computer system 2400 and displayed using the output devices 2480.

One of ordinary skill in the art will recognize that the computer system2400 may be embodied in other specific forms without deviating from thespirit of the invention. For instance, the computer system may beimplemented using various specific devices either alone or incombination. For example, a local Personal Computer (PC) may include theinput devices 2470 and output devices 2480, while a remote PC mayinclude the other devices 2410-2450, with the local PC connected to theremote PC through a network that the local PC accesses through itsnetwork connection 2490 (where the remote PC is also connected to thenetwork through a network connection).

The bus 2410 collectively represents all system, peripheral, and chipsetbuses that communicatively connect the numerous internal devices of thecomputer system 2400. In some cases, the bus 2410 may include wirelessand/or optical communication pathways in addition to or in place ofwired connections. For example, the input devices 2470 and/or outputdevices 2480 may be coupled to the system 2400 using a wireless localarea network (W-LAN) connection, Bluetooth®, or some other wirelessconnection protocol or system.

The bus 2410 communicatively connects, for example, the processor 2420with the system memory 2430, the ROM 2440, and the permanent storagedevice 2450. From these various memory units, the processor 2420retrieves instructions to execute and data to process in order toexecute the processes of some embodiments. In some embodiments theprocessor includes an FPGA, an ASIC, or various other electroniccomponents for execution instructions.

The ROM 2440 stores static data and instructions that are needed by theprocessor 2420 and other modules of the computer system. The permanentstorage device 2450, on the other hand, is a read-and-write memorydevice. This device is a non-volatile memory unit that storesinstructions and data even when the computer system 2400 is off. Someembodiments of the invention use a mass-storage device (such as amagnetic or optical disk and its corresponding disk drive) as thepermanent storage device 2450.

Other embodiments use a removable storage device (such as a floppy disk,flash drive, or CD-ROM) as the permanent storage device. Like thepermanent storage device 2450, the system memory 2430 is aread-and-write memory device. However, unlike storage device 2450, thesystem memory 2430 is a volatile read-and-write memory, such as a randomaccess memory (RAM). The system memory stores some of the instructionsand data that the processor needs at runtime. In some embodiments, thesets of instructions and/or data used to implement the invention'sprocesses are stored in the system memory 2430, the permanent storagedevice 2450, and/or the read-only memory 2440. For example, the variousmemory units include instructions for processing multimedia items inaccordance with some embodiments.

The bus 2410 also connects to the input devices 2470 and output devices2480. The input devices 2470 enable the user to communicate informationand select commands to the computer system. The input devices includealphanumeric keyboards and pointing devices (also called “cursor controldevices”). The input devices also include audio input devices (e.g.,microphones, MIDI musical instruments, etc.) and video input devices(e.g., video cameras, still cameras, optical scanning devices, etc.).The output devices 2480 include printers, electronic display devicesthat display still or moving images, and electronic audio devices thatplay audio generated by the computer system. For instance, these displaydevices may display a graphical user interface (GUI). The displaydevices include devices such as cathode ray tubes (“CRT”), liquidcrystal displays (“LCD”), plasma display panels (“PDP”),surface-conduction electron-emitter displays (alternatively referred toas a “surface electron display” or “SED”), etc. The audio devicesinclude a PC's sound card and speakers, a speaker on a cellular phone,Bluetooth® earpiece, etc. Some or all of these output devices may bewirelessly or optically connected to the computer system.

Finally, as shown in FIG. 24, bus 2410 also couples computer 2400 to anetwork 2490 through a network adapter (not shown). In this manner, thecomputer can be a part of a network of computers (such as a local areanetwork (“LAN”), a wide area network (“WAN”), an Intranet, or a networkof networks, such as the Internet. For example, the computer 2400 may becoupled to a web server (network 2490) so that a web browser executingon the computer 2400 can interact with the web server as a userinteracts with a GUI that operates in the web browser.

As mentioned above, some embodiments include electronic components, suchas microprocessors, storage and memory that store computer programinstructions in a machine-readable or computer-readable medium(alternatively referred to as computer-readable storage media,machine-readable media, or machine-readable storage media). Someexamples of such computer-readable media include RAM, ROM, read-onlycompact discs (CD-ROM), recordable compact discs (CD-R), rewritablecompact discs (CD-RW), read-only digital versatile discs (e.g., DVD-ROM,dual-layer DVD-ROM), a variety of recordable/rewritable DVDs (e.g.,DVD-RAM, DVD-RW, DVD+RW, etc.), flash memory (e.g., SD cards, mini-SDcards, micro-SD cards, etc.), magnetic and/or solid state hard drives,read-only and recordable blu-ray discs, ultra density optical discs, anyother optical or magnetic media, and floppy disks. The computer-readablemedia may store a computer program that is executable by a device suchas an electronics device, a microprocessor, a processor, amulti-processor (e.g., an IC with several processing units on it) andincludes sets of instructions for performing various operations. Thecomputer program excludes any wireless signals, wired download signals,and/or any other ephemeral signals.

Examples of hardware devices configured to store and execute sets ofinstructions include, but are not limited to, ASICs, FPGAs, programmablelogic devices (“PLDs”), ROM, and RAM devices. Examples of computerprograms or computer code include machine code, such as produced by acompiler, and files including higher-level code that are executed by acomputer, an electronic component, or a microprocessor using aninterpreter.

As used in this specification and any claims of this application, theterms “computer”, “computer system”, “server”, “processor”, and “memory”all refer to electronic or other technological devices. These termsexclude people or groups of people. For the purposes of thisspecification, the terms display or displaying mean displaying on anelectronic device. As used in this specification and any claims of thisapplication, the terms “computer readable medium”, “computer readablemedia”, “machine readable medium”, and “machine readable media” areentirely restricted to non-transitory, tangible, physical objects thatstore information in a form that is readable by a computer. These termsexclude any wireless signals, wired download signals, and/or any otherephemeral signals.

It should be recognized by one of ordinary skill in the art that any orall of the components of computer system 2400 may be used in conjunctionwith the invention. Moreover, one of ordinary skill in the art willappreciate that any other system configuration may also be used inconjunction with the invention or components of the invention.

While the invention has been described with reference to numerousspecific details, one of ordinary skill in the art wilt recognize thatthe invention can be embodied in other specific forms without departingfrom the spirit of the invention. Moreover, while the examples shownillustrate many individual modules as separate blocks, one of ordinaryskill in the art would recognize that some embodiments may combine thesemodules into a single functional block or element. One of ordinary skillin the art would also recognize that some embodiments may divide aparticular module into multiple modules. Furthermore, specific details(such as details shown in FIGS. 1-23) are given as an example and it ispossible to use different circuit implementations to achieve the sameresults without deviating from the teachings of the invention. The words“embodiment” and “embodiments” are used throughout this specification torefer to the embodiments of the current invention.

One of ordinary skill in the art would understand that the invention isnot to be limited by the foregoing illustrative details, but rather isto be defined by the appended claims.

What is claimed is:
 1. A wireless radio frequency (RF) transmittingdevice for wirelessly charging a plurality of electronic devices, the RFtransmitting device comprising: one or more directional antennas todirect an RF beam to an antenna of each of the plurality of electronicdevices; a module that provides power to the one or more directionalantennas; and a database that stores a power schedule information forcharging the plurality of electronic devices authorized to receive theRF beam from the one or more directional antennas; wherein the RFtransmitting device charges batteries of the plurality of electronicdevices using the one or more directional antennas to direct the RF beamto the antenna of each of the plurality of electronic devices, inaccordance with the power schedule information stored in the database.2. The RF transmitting device of claim 1, wherein the power scheduleinformation provides a power transmission schedule based on a chargingpriority of each of the plurality of electronic devices.
 3. The RFtransmitting device of claim 2 further comprising a user interface for auser to enter the charging priority of each of the plurality ofelectronic devices.
 4. The RF transmitting device of claim 2, whereinthe RF transmitting device monitors a power status of each of theplurality of electronic devices to determine the charging priority ofeach of the plurality of electronic devices.
 5. The RF transmittingdevice of claim 2, wherein the RF transmitting device receives thecharging priority of a first electronic device of the plurality ofelectronic devices from the first electronic device.
 6. The RFtransmitting device of claim 1, wherein the power schedule informationspecifies a longer period of power transmission to a first electronicdevice of the plurality of electronic devices than a second electronicdevice of the plurality of electronic devices.
 7. The RF transmittingdevice of claim 1, wherein the one or more directional antennas are partof an antenna array.
 8. The RF transmitting device of claim 1 furthercomprising: a communication module using short distance wireless signalsfor data communications with the plurality of electronic devices.
 9. TheRF transmitting device of claim 1, wherein the RF transmitting devicecharges a first electronic device of the plurality of electronic devicesto a pre-determined low level.
 10. A wireless radio frequency (RF)transmitting device for wirelessly charging a plurality of electronicdevices, the RF transmitting device comprising: one or more directionalantennas to direct an RF beam to an antenna of each of the plurality ofelectronic devices; a module that provides power to the one or moredirectional antennas; and a database that stores a charging priority forcharging the plurality of electronic devices authorized to receive theRF beam from the one or more directional antennas; wherein the RFtransmitting device charges batteries of the plurality of electronicdevices using the one or more directional antennas to direct the RF beamto the antenna of each of the plurality of electronic devices, inaccordance with the charging priority stored in the database.
 11. The RFtransmitting device of claim 10 further comprising a user interface fora user to enter the charging priority of each of the plurality ofelectronic devices.
 12. The RF transmitting device of claim 10, whereinthe RF transmitting device monitors a power status of each of theplurality of electronic devices to determine the charging priority ofeach of the plurality of electronic devices.
 13. The RF transmittingdevice of claim 10, wherein the RF transmitting device receives thecharging priority of a first electronic device of the plurality ofelectronic devices from the first electronic device.
 14. The RFtransmitting device of claim 10 further comprising: a communicationmodule using short distance wireless signals for data communicationswith the plurality of electronic devices.
 15. A method for use by awireless radio frequency (RF) transmitting device for wirelesslycharging a plurality of electronic devices, the method comprising:providing power to one or more directional antennas of the RFtransmitting device, the RF transmitting device having a database thatstores a power schedule information for charging the plurality ofelectronic devices authorized to receive the RF beam from the one ormore directional antennas; and directing an RF beam, using one or moredirectional antennas of the RF transmitting device, to an antenna ofeach of the plurality of electronic devices to charge batteries of theplurality of electronic devices, in accordance with the power scheduleinformation stored in the database.
 16. The method of claim 15, whereinthe power schedule information provides a power transmission schedulebased on a charging priority of each of the plurality of electronicdevices.
 17. The method of claim 16 further comprising: receiving thecharging priority of each of the plurality of electronic devices, usinga user interface of the RF transmitting device.
 18. The method of claim16 further comprising: monitoring a power status of each of theplurality of electronic devices to determine the charging priority ofeach of the plurality of electronic devices.
 19. The method of claim 16further comprising: receiving the charging priority of a firstelectronic device of the plurality of electronic devices from the firstelectronic device.
 20. The method of claim 15, wherein the powerschedule information specifies a longer period of power transmission toa first electronic device of the plurality of electronic devices than asecond electronic device of the plurality of electronic devices.